This invention relates to a band-thickness adjusting device for a portable packing machine, particularly to one easy to handle and quick to adjust.
An adjusting device for a conventional portable packing machine shown in FIGS. 1, 2 and 3 includes a crutch rod 11, a handling rod 12, and a stop member 13. The crutch rod and the handling rod have respectively female teeth 111 and male teeth 121 formed in a front center to engage with each other. The crutch rod 11 has a stop plate 112 formed in a front end, and the handling rod 12 has a blocking member 131 to correspond to the stop plate 112, and an eccentric round post 122 formed in a proper portion and pivotally fitted with a press rod 14. When a grip 123 provided at a side of the handling rod 12 is pressed down, the eccentric post 122 rotates for an eccentric distance to press a press rod 14 down for a certain distance so that a friction head 15 located under the bottom end of the press rod 14 is pressed down onto a stationary friction head 16, performing fusing function by friction to a packing band 17 sandwiched between the two friction heads 15 and 16.
When the two friction heads 15 and 16 sandwich the packing band 17, a proper force has to be used so as to avoid too large pressure, or otherwise load on a motor of the adjusting device may be too large to cause irregular operation. In order to apply to packing bands of different thickness, the adjusting device 10 should have the crutch rod 11 provided with the stop plate 112, which has to move in a limited distance to contact a blocking plate 131 of the s top member 13. If the adjusting device 10 is to be adjusted to the thickness of a packing band 17, referring to FIGS. 2 and 3, at first manually hold and pull out a ball-shaped end 113 of the crutch rod 11, disengaging the female teeth 111 from the male teeth 121. Then rotate the crutch rod 11 to a preset angle, and then release it. Then the female teeth 111 automatically move to engage the male teeth 121 by elasticity of a spring 18. Thus alteration of the relative positions of the female and the male teeth 15 and 16 may cause alteration of the moving distance between the stop plate 112 and the blocking plate 131. So when the grip 123 is pressed down, the press rod 14 is pressed down, with the crutch rod 11 also rotated. So when the stop plate 112 contacts the blocking plate 131, the handling rod 12 is also stopped, impossible to move any more, with the friction head 15 pressing on the packing band 17. Thus the adjusting device 10 can change the moving distance of the stop plate 112 to the blocking plate 131 by adjusting the relative positions of the crutch rod 11 and the handling rod 12, controlling the moving-down distance of the pressing rod 14 to suit to different thickness of the packing bands 17.
Although the conventional adjusting device 10 can perform adjusting function to suit to a variety of packing bands having different thickness, its structure is too complicated to result in a high cost. Moreover, the adjusting device 10 is hidden in a machine body 19 as shown in FIG. 3, hardly possible to control an adjusting distance in handling with accuracy and quickness, not ideal in handling. Besides, the smallest distance to be adjusted is limited by every two teeth of the female teeth 111 and the male teeth 121, with the distance impossible to be adjusted freely.
The purpose of the invention is to offer a band-thickness adjusting device for a portable packing machine, which has an adjusting shaft and an activating shaft pivotally and eccentrically fitted with the adjusting shaft. An eccentric moving distance of the activating rod presses a press rod to move down to change the gap between two friction heads of a fusing device so as to adjust a pressure suitable to different thickness of packing bands. The band-thickness adjusting device has a special simple structure to facilitate handling with quickness.